What reportedly happened: The flight instructor was demonstrating a soft-field takeoff to his student. During the takeoff roll, he applied full back pressure on the yoke, heard the stall horn, and lowered the nose.

As the plane left the ground, the CFI heard the stall horn a second time. The right wing began to rise as the plane reached an estimated altitude of 20 feet. The CFI checked that the throttle was full forward, but the airplane would not accelerate. As the plane continued to turn left it departed the left side of the runway and the left wing hit a runway information sign.

The plane came to a stop in the grass off the left side of the runway. The left wing’s forward spar was damaged and the left fuel tank was ruptured. The right wing’s outer 4 feet was bent up and the engine’s firewall was wrinkled.